Student research project attracts European partners and NSF funding

Mediterranean seagrass study is now an international collaboration, and the two UC Santa Cruz students who started it have a grant to extend their findings

Senior marine biology majors Hannah Perlkin and Emily Tucker will continue their research on seagrass with support from the National Science Foundation. (Photo by Carolyn Lagattuta)
Hannah Perlkin holds a flower of the seagrass Posidonia oceanica after a dive off the coast of Corsica. (Photo by Emily Tucker)

Hannah Perlkin and Emily Tucker didn't have grand ambitions when they enrolled in the Marine Ecology Field Quarter course at UC Santa Cruz last fall. Then they began making some interesting discoveries about Neptune grass, the iconic seagrass of the Mediterranean Sea, and they weren't the only ones excited by their findings. Leading European seagrass researchers are also interested, and the U.S. National Science Foundation (NSF) has awarded a grant enabling the students, both senior marine biology majors, to continue their research in the Mediterranean and work with European collaborators.

"I'm still coming to grips with how amazing this opportunity is," Tucker said.

The Marine Ecology Field Quarter is no ordinary class. After two rounds of interviews, 30 students are admitted, and it is the only class they take for the quarter. It starts with intensive classroom study of marine ecology, and the second half is spent in the field at a remote marine lab where the students conduct independent research. Last fall, the class went to a marine research station in Corsica, France.

Peter Raimondi and Giacomo Bernardi, professors of ecology and evolutionary biology at UCSC, have been teaching this course since 1998. "In ecology and evolutionary biology, if you don't take field classes you won't be trained very well," Raimondi said. "With these immersion classes, we isolate the students in the field so there are no distractions and they can focus on their research."

As Tucker put it, "In the field quarter classes, you learn by doing."

She and Perlkin knew in advance that they wanted to work together and they wanted to study seagrass. Neptune grass (Posidonia oceanica) is the dominant habitat-forming species in the Mediterranean, where it forms extensive underwater meadows that play an ecological role similar to that of the kelp forests along the California coast.

One of the first things Perlkin and Tucker discovered was that the seagrass was starting to flower. That may not sound very exciting, but it's been nearly ten years since the last time the seagrass meadows flowered. The students quickly changed their plans and designed a study to look at patterns of flowering. Raimondi sent an email to Ester Serrão, a marine ecologist in Portugal he has collaborated with in his own research, and she contacted other seagrass researchers to confirm that Posidonia was flowering throughout the Mediterranean.

The students, meanwhile, were not only diving into the sea to collect data, they were diving into the scientific literature to learn all they could about Posidonia. "Something just sparked and we got really motivated and focused," Tucker said.

That kind of transformative experience is exactly what the field courses are intended to foster, Raimondi said. "These two students were engaged in the class from the beginning, but when they discovered the flowering and saw where their observations were leading, it was a completely different mentality. As a teacher, this is just what you hope to see in your students," he said.

"When we started finding what looked like flowers, we were very excited," Perlkin said. "We were also a little panicky at that point about changing our project, but Pete and Giacomo were both very encouraging. They could tell it was something we were really excited about."

The students set out to look at how flowering changes with depth and light levels, counting inflorescences along transects set up perpendicular to the shore. As expected, they found increased flowering in shallow water where more light reaches the bottom. Then they decided to do some transects parallel to shore at a constant depth. Those results showed an interesting pattern of variations in flowering.

Posidonia is a "clonal" species, spreading by vegetative growth so that patches of the seafloor are covered by clones of a single individual. In a seagrass meadow, however, there's no way to tell where one clone ends and another begins without doing extensive sampling and genetic analysis.

"Hannah and Emily saw that the flowering was really patchy. Then they read in the literature that genetic studies showed the clones grow in patches that are around the same size as what they were seeing in the flowering patterns," Raimondi said. "So maybe the clones differ in their ability to flower. If so, that opens up a whole new avenue of research."

It also has implications for seagrass restoration efforts, he said. Seagrass meadows are declining in the Mediterranean and elsewhere around the world. Posidonia is an especially long-lived and slow-growing species, and restoration efforts have not had much success. "You can do transplants, but it's tricky because you have to have a donor population, and the transplants tend not to grow very much," Raimondi said.

Because flowering is so rare, sexual reproduction in Posidonia has not been well studied. More strategic approaches to seagrass restoration might be devised if scientists had a better understanding of flowering and of the relative importance of clonal spread versus the establishment of new plants from seed, Raimondi said.

For Perlkin and Tucker, the possibility of using genetics to sort out what was going on in the seagrass meadows had always seemed frustratingly out of reach. "We kept bringing it up jokingly," Perlkin said. "Like, how cool would that be, to use genetics to figure out who's who out there. Genomics is increasingly affordable, but for two undergraduates it was only a hypothetical possibility."

That changed on their last day in Corsica when Serrão, whose research includes genetic studies of seagrasses, invited the students to come to her lab in Portugal. Through Serrão, Raimondi had been in touch with seagrass researchers throughout the Mediterranean, sharing emerging results from Perlkin and Tucker's study and initiating a collaborative effort to collect samples for genetic analysis.

As for funding, Raimondi told the students that if they were really interested in pursuing this, there are ways to pay for it. For the class, the students had to write a paper on their research project, and Raimondi used Perlkin and Tucker's paper as the basis for an NSF grant proposal. He applied through NSF's Rapid Response Research funding mechanism, because the flowering event is a research opportunity that will soon pass.

"I think [NSF] liked not just the scientific merit of the project, but also that it was an undergraduate research project that had blossomed into something bigger. They're very much interested in improving science education by getting students engaged in research," Raimondi said.

The $85,000 NSF grant will enable Perlkin and Tucker to work with European researchers collecting samples for genetic analysis in three locations in the Mediterranean: Magaluf, Majorca; Calvi, Corsica; and Split, Croatia. The researchers have already been collecting seagrass samples according to a consistent study design. When the students return in April, the seagrass will be fruiting and they will be able to collect fruit samples. Then they will go to Serrão's lab in Portugal to learn her methods for genetic analysis.

Luckily, Perlkin and Tucker are both on track to graduate early, so they will be done with their coursework at the end of winter quarter and free to spend the next two months in Europe. When they return to Santa Cruz, they'll go to work in Bernardi's lab, where he plans to develop new genomic markers for the seagrass research.

While Perlkin and Tucker's project has led to remarkable opportunities, it is not the only success story in the class, according to Raimondi. Many of the 14 student projects in Corsica were exceptional, he said, and several groups are now writing up their results for publication in scientific journals. Raimondi, who chairs the Department of Ecology and Evolutionary Biology, said a recent survey of nearly 300 former students indicated that the immersion classes have dramatic benefits for students in terms of their job prospects and careers.

"UCSC is unique in its commitment to field classes and has been really supportive of the immersion model our department has developed," he said. "This seagrass project is a good example of the value of field classes, the quality of our undergraduates, and the emphasis that NSF places on fostering undergraduate research."